Smoking and Tobacco Control Monograph No. 7 
emitted into the surrounding air between puffs from the end of the smolder- 
ing cigarette. Sidestream smoke is the major source of environmental tobacco 
smoke (ETS). 
Although SS and MS smoke have qualitatively similar chemical 
compositions, the respective quantities of individual smoke constituents 
can be quite different (U.S. Department of Health and Human Services, 
1987 and 1989). For example, in studies of nonfilter cigarettes smoked 
by machines, the yield of CO in undiluted SS smoke was 2.5- to 4.7-fold 
that of MS smoke, whereas the corresponding SS/MS ratio for N- 
nitrosodimethylamine (NDMA), an animal carcinogen, was 0.2 
(U.S. Department of Health and Human Services, 1989). In one compilation 
of toxic and tumorigenic agents in cigarette smoke, the SS/MS ratio ranged 
from 0.03 to 130 (Hoffmann and Hecht, 1990). In another study, the 
concentration of the carcinogen 4-aminobiphenyl in undiluted SS smoke 
was 32-fold that of MS smoke. The SS smoke from so-called reduced-yield 
cigarettes does not necessarily have reduced emissions of toxic and 
carcinogenic chemicals (Adams et al., 1987; Rando et al., 1992). 
Whereas exposure to SS smoke depends on the distance from the 
burning cigarette and conditions of ventilation, the higher concentrations 
of certain toxic and carcinogenic chemicals in SS smoke result in measurable 
levels of these chemicals in nonsmokers exposed to ETS. For example, 
nonsmokers exposed to relatively high concentrations of SS smoke have 
detectable urinary levels of the metabolites of the tobacco-specific 
nitrosamine 4-(methylnitrosamine)-l-(3-pyridil)-l-butanone (NNK) 
(Hecht et al., 1993). Young children exposed to ETS via their smoking 
mothers have detectable levels of PAH-albumin adducts in their blood 
(Crawford et al., 1994). 
Exposures to specific chemical agents in ETS can in turn produce 
pathological effects in humans and in animal models. The CO in SS smoke 
reduces the blood's ability to deliver oxygen to the heart, an effect that is 
especially important in patients with coronary heart disease (CHD) (Sheps et 
al., 1990). Secondhand cigarette smoke activates blood platelets, which in 
turn play a role in the development of atherosclerotic plaques in CHD 
(Glantz and Parmley, 1995). 
I he remainder of this chapter focuses on the chemical components of 
MS smoke and their health effects on cigarette smokers; however, the 
components of SS smoke and their health effects on nonsmokers cannot 
be ignored. 
MAJOR HEALTH The major health effects of cigarette smoke include: 
cancer; 
noncancerous lung diseases; 
atherosclerotic diseases of the heart and blood vessels; and 
toxicity to the human reproductive system. 
EFFECTS OF 
CIGARE n E SMOKE . 
60 
